Preheat oven to 450 degrees. Mix dry ingredients. Make a well in the middle and add buttermilk. Stir just enough to moisten. Turn dough onto floured board and gently work with hands for about a minute. Shape into a round loaf and place in an 20 cm round cakepan. Cut an "X" across the top of the dough with a knife. Reduce heat to 350 degrees and bake 55 to 60 minutes. Bread will be done when it sounds hollow when you rap on the bottom.